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Advances in plant photobiology: let’s light it up once again
No full textLight serves as a crucial environmental cue regulating plant growth and development. The light signaling pathway in plants initiates with the detection of light by photoreceptors and culminates in the alteration of the transcriptome and subsequent phenotypic modifications. A sophisticated and interconnected signaling network operates downstream of the photoreceptors to modulate the expression of the light-regulated genes. In this Special Issue, we discuss several new roles of light signal components together with interactions of this pathway with other signaling networks to regulate various physiological and developmental processes. The evolution of components of the light signaling pathway is also highlighted.
The role of light in regulating various aspects of plant development has fascinated scientists for a long time. Several groups spread all over the world are engaged in photobiology research. In January 2024, the EMBO-ISPP (International Symposium on Plant Photobiology) was conducted at NISER Bhubaneswar followed by a satellite meeting at IISER Bhopal, India. At this meeting, various advances in the field of plant photobiology were discussed, which form the basis of this Special Issue. The issue comprises several reviews that outline new developments in the field, as highlighted below
Mapping dihydropteroate synthase evolvability through identification of a novel evolutionarily critical substructure
No full textProtein evolution shapes pathogen adaptation-landscape, particularly in developing drug resistance. The rapid evolution of target proteins under antibiotic pressure leads to escape mutations, resulting in antibiotic resistance. A deep understanding of the evolutionary dynamics of antibiotic target proteins presents a plausible intervention strategy for disrupting the resistance trajectory. Mutations in Dihydropteroate synthase (DHPS), an essential folate pathway protein and sulfonamide antibiotic target, reduce antibiotic binding leading to anti-folate resistance. Deploying statistical analyses on the DHPS sequence-space and integrating deep mutational analysis with structure-based network-topology models, we identified critical DHPS subsequences. Our frustration landscape analysis suggests how conformational and mutational changes redistribute energy within DHPS substructures. We present an epistasis-based fitness prediction model that simulates DHPS adaptive walks, identifying residue positions that shape evolutionary constraints. Our optimality analysis revealed a substructure central to DHPS evolvability, and we assessed its druggability. Combining evolution and structure, this integrated framework identifies a DHPS substructure with significant evolutionary and structural impact. Targeting this region may constrain DHPS evolvability and slow resistance emergence, offering new directions for antibiotic development
Water‐soluble polymeric probe with naphthalimide pendants for fluorimetric formaldehyde sensing.
No full textFormaldehyde (FA) is a common raw material extensively used in various industrial applications. However, FA is a known carcinogen and poses significant risks to human health. Therefore, developing a sensitive and selective probe for detecting FA is crucial. Herein, a naphthalimide-based water-soluble fluorescent polymeric probe for selective detection of FA in an aqueous medium at physiological pH is presented. The aromatic hydrazine units present in the side chains of the polymer react with FA through an addition-elimination reaction with the formation of hydrazone derivative, which halts the photoelectron transfer (PET) mechanism within the polymer, leading to a “turn-on” in green fluorescence. The formation of hydrazone is confirmed by electrospray ionization mass spectrometry (ESI-MS) analysis for a model reaction of (6-hydrazinyl-2-(2-hydroxyethyl)-1H-benzo[de]isoquinoline-1,3(2H)-dione, SM) with FA. The sensing mechanism through a PET on–off is supported by density functional theory (DFT) calculation. The probe demonstrates remarkable sensitivity, detecting FA concentrations as low as 1.7 µm, and shows a five-fold fluorescence intensity increase within 10 min when exposed to 10 µm formaldehyde. Additionally, the probe offers selective detection of FA over other analytes via fluorometric methods. This study represents a significant advancement in developing sensitive and selective polymeric probes
Microwave absorbing fluorescent copolymer with enhanced anti‐counterfeiting security features.
No full textCounterfeiting is a significant issue affecting various sectors, including banking, insurance, pharmaceuticals, and commercial goods. A combination of security elements creates a multilayered protection for counterfeiting prevention, ensuring diverse authentication against fraud and unauthorized duplication. To design microwave-absorbing polymers with optical transparency and fluorescence, methyl methacrylate (MMA) was copolymerized using reversible addition-fragmentation chain transfer (RAFT) polymerization with 2-(dimethylamino)ethyl methacrylate (DMAEMA) and pyrene methacrylate (PyMA). The amine moieties from the DMAEMA repeating units in the copolymer were ionized at room temperature by treating with hydrochloric acid (HCl) or trifluoroacetic acid (TFA), resulting in copolymer salts with an ion-pair complex. Optical transparency, fluorescent properties, and ionic conductivity of the copolymer salts with chloride (Cl⁻)/trifluoroacetate (TFA−) counter anions and pyrene moieties were studied in detail. Optically transparent fluorescent copolymers with partially mobile Cl⁻ counter anions witnessed strong microwave absorption due to multiple reflections from structural and physical anisotropies. This study highlights a strategy for designing a material that combines multiple features like microwave absorption, optical transparency, and characteristic fluorescence emission, within a single material system, a key area of research in the security and communication industries
Limantrafin‐bodipy conjugates reduce stemness and metastatic potential via superoxide driven phototherapy in triple negative breast cancer.
No full textType-I photosensitizers are advantageous for treating hypoxic tumors compared to singlet oxygen (1O2)-based photodynamic therapy (PDT) agents. However, efficient and selective Type-I reactive oxygen species (ROS) generators remain scarce. Here, Limantrafin (Notch1 transcription inhibitor) conjugated BODIPY photosensitizer is reported that selectively produces superoxide radicals (O₂•⁻) upon green light irradiation and exhibits a significantly higher phototherapeutic index (PI) than its structural analog. Theoretical studies and delayed photoluminescence measurements indicate that efficient intersystem crossing from the singlet excited state (S₁) to an intermediate triplet (T₂), followed by relaxation to a long-lived triplet state (T₁), may facilitate effective electron transfer to molecular oxygen. In triple-negative breast cancer (TNBC) cells (MDA-MB-231), the lead compound shows significantly high PI (>3700) by low-intensity green light irradiation. Furthermore, encapsulation in glycopolymer-based nanoparticles enhances cancer cell selectivity and therapeutic efficacy. Interestingly, there is also a reduction in multiple stemness-associated gene expression and downregulation of Cluster of Differentiation 44 (CD44) and Intercellular Adhesion Molecule 1 (ICAM-1/CD54) surface protein markers that promote stemness and immune evasion in TNBC. This dual action may impair tumor aggressiveness, recurrence, and promote immunogenic cell death. The findings highlight that the conjugation of the Notch1 inhibitor, Limantrafin, with BODIPY widens the horizon of Type-I photosensitizers to design next-generation PDT agents
Bayesian network based probabilistic approach for uncertainty analysis of earthquake induced landslides.
No full textIn this study, a unique approach is used to calculate the likelihood of the safety factor and permanent displacement of natural slopes under earthquake shaking. The proposed approach was constructed using probabilistic modeling of landslide instability based on the Bayesian Network technique. First, the pseudo-static factor of safety was computed, considering it an uncertain parameter. Then, the permanent displacement of failure mass was estimated through probabilistic analysis considering the effect of critical and peak horizontal acceleration. In the process of probabilistic analysis, soil and slope properties (cohesion, friction angle, unit weight, slope angle, and failure depth) and peak horizontal acceleration were considered as random variables distributed as normal and exponential functions, respectively. To illustrate the applicability of the proposed approach, a hypothetical infinite slope was adopted from past literature. The results showed that due to the event of an earthquake, the slope might experience permanent displacement. Finally, based on the variation of permanent displacement, the likelihood of landslide occurrences was estimated. Validation of the study was established by comparing the outcomes with the results obtained from the multivariate probabilistic approach, first-order reliability method, and Monte Carlo simulation. To demonstrate the practical applicability of the proposed framework, a case study of earthquake-induced landslides was taken to estimate the factors of safety and permanent displacement probabilistically. The methodology presented in this study would lead to an estimation of landslide failures by taking uncertainties into account, which would increase the safety of city dwellers
Prostate-Related Germline Variant Frequencies Detected in a Cohort of Men With Metastatic Prostate Cancer in Northern India
No full textPurpose
Although prostate cancer is generally associated with favorable outcomes, metastatic disease remains incurable. Additionally, a subset of individuals with high-risk or metastatic disease are likely to harbor at least one germline variant in known prostate cancer association genes. Because of differences in cohort selection and sequencing strategies, the prevalence of germline variants in global populations is unclear.
Methods
A whole-exome sequencing (WES) approach was used to explore germline variants in a cohort of patients with metastatic prostate cancer from India. In total, 276 individuals treated at the All India Institute of Medical Sciences in New Delhi, India, were prospectively and consecutively recruited. Blood specimens underwent standard WES and bioinformatic analysis to determine the prevalence of pathogenic and likely pathogenic (PV/LPV) prostate cancer variants, which were then assessed for associations with clinical features.
Results
In total, PV/LPVs were detected in 11% of individuals across eight genes linked to prostate cancer, most frequently in BRCA2 (3.98%). The distribution reflects previously published findings from other global cohorts, although frequencies in the prevalence of specific variants differ slightly. No relationship between variant status and clinical features were detected, although analysis of a larger cohort may show otherwise.
Conclusion
These results indicate that germline screening for prostate cancer following existing guidelines yield similar variant detection frequencies when focusing on individuals with metastatic disease in the Indian context. In summary, some men are more likely to develop an advanced form of metastatic prostate cancer than others because of differences in their genes, known as variants. This study looked at the how many of these variants are in a group of patients from India. We found that the number of variants in this group was similar to those from other parts of the world, including more found in a gene called BRCA2
Harnessing the potential of amide-linked Gemini surfactants for corrosion inhibition and antimicrobial activity: From molecular design to functional performance
No full textGemini surfactants, also called Gemini, especially those with quaternary ammonium head groups, are recognized for their distinctive aggregation behavior and enhanced structure–activity relationships. The unique dual-head and dual-tail structure of Gemini grants them superior surface activity, allowing them to effectively lower surface and interfacial tension. To investigate the self-assembly behavior and surface-active properties that make them suitable as anticorrosion and antimicrobial agents, a series of cationic Gemini featuring amide bonds and varying alkyl chain lengths were synthesized. Surface activity and self-assembly characteristics of these cationic Gemini were analyzed using methods such as surface tension, electrical conductivity, fluorescence, and isothermal titration calorimetry. The findings revealed that these Gemini possess enhanced surface-active and self-assembly properties in comparison to traditional single-tail, monoheaded surfactants. Thermodynamic studies confirmed that these Gemini self-assemble spontaneously in water above a relatively low threshold concentration, with the self-assembly process becoming less favorable as the alkyl chain length decreased. The length of the chains also affected the size and shape of the aggregates formed. These Gemini have been shown to exhibit remarkable anticorrosion properties on steel surface. The performance of these compounds as corrosion inhibitors showed a clear dependence on chain length, with the shortest chain length Gemini providing the highest inhibition efficiency. These Gemini have also exhibited pronounced antibacterial activities against Escherichia coli (DH5alpha) and Staphylococcus aureus bacteria
Electric Field-Tunable Superconductivity with Competing Orders in Twisted Bilayer Graphene near the Magic Angle
No full textSuperconductivity (SC) in twisted bilayer graphene (tBLG) has been explored by varying carrier concentrations, twist angles, and screening strength, with the aim of uncovering its origin and possible connections to strong electronic correlations in narrow bands and various resulting broken symmetries. However, the link between the tBLG band structure and the onset of SC and other orders largely remains unclear. In this study, we address this crucial gap by examining in situ band structure tuning of a near magic-angle (θ ≈ 0.95°) tBLG device with a displacement field (D) and reveal competition between SC and other broken symmetries. At zero D, the device exhibits superconducting signatures without the resistance peak at half-filling, a characteristic signature with a strong electronic correlation. As D increases, the SC is suppressed, accompanied by the appearance of a resistance peak at half-filling. Hall density measurements reveal that at zero D, SC arises around the van Hove singularity (vHs) from an isospin or spin-valley unpolarized band. At higher D, the suppression of SC coincides with broken isospin symmetry near half-filling with lifted degeneracy (gd ∼ 2). Additionally, as the SC phase becomes weaker with D, vHs shifts to higher fillings, highlighting the modification of the underlying band structure with the applied electric field. These findings, with recent theoretical study on SC in tBLG, highlight the competition, rather than being connected concomitantly, between SC and other orders promoted by broken symmetries
Structurally engineered so2–releasing polymeric nanoassembly for broad-spectrum antibacterial activity.
No full textCationic antimicrobial agents are widely recognized for combating microbial infections through their membrane–disruptive properties. Recently, sulfur dioxide (SO2) gas therapy has emerged as a promising alternative for treating diseases, including bacterial infections. However, current systems often target only specific bacterial strains. Herein, we present amphiphilic alternating copolymers, DAPx (x = 1, 2, 3), incorporating cationic residues and thiol-responsive SO2-releasing moieties. In aqueous environments, DAPx copolymers self-assemble into micellar nanoassemblies (DAPxNp), exposing hydrophilic cationic residues outward and encapsulating hydrophobic SO2-releasing moieties within the core to enable controlled and sustained release of SO2 in the presence of glutathione (GSH). In vitro studies reveal excellent biocompatibility of DAP2 Np with broad-spectrum antibacterial activity against both Gram-positive (Bacillus subtilis, Staphylococcus aureus) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria. Mechanistic investigations confirm bacterial eradication via membrane disruption and reactive oxygen species generation. This study underscores the remarkable efficacy of SO2-releasing cationic polymers in resisting bacterial infections